Early prediction of response to a chemotherapeutic treatment is of great value to avoid unnecessary toxicity of ineffective treatment and to get a chance to receive another effective treatment at an early stage.
Increased uptake of 18F-fluorodeoxyglucose (FDG) measured by positron emission tomography (PET) reflects glucose metabolism and proliferative activity of tumor cells. Metabolic imaging with FDG-PET has been used for staging, restaging, and evaluating treatment efficacy in various cancers. Some studies have indicated that FDG-PET is useful for the early evaluation of tumor response to anticancer drugs.
FDG-PET has been used to predict chemotherapeutic efficacy of Ewing's sarcoma tumors. However, the value of FDG-PET scans performed at an early point in a treatment regimen has not been heretofore realized. Specifically, whether the observation of an effect on tumor metabolism (or lack of an effect) at an early point will predict overall sensitivity of the tumor to a given therapy is uncertain. Clearly, a study that clarifies this uncertainty would be useful and would suggest a new method for quick evaluation of Ewing's sarcoma tumor sensitivity.